To your first question
What utility is there in knowing the name of a fallacy used in a particular argument?
Contrary to other answers and comments more generous to the human condition than I am, this is unlikely to be out of a sense of "being able to communicate with other experts" or "helping to understand the problem" or just a shorthand way of expressing the issue. It is vastly more likely to be an attempt to win an argument without having to actually work out for oneself why the opponent's logic is wrong because an expert has already said it is (by which I mean Appeal to Authority, but it didn't take me long to write it the long way).
Names obviously help to communicate with other experts as with the use of latin names in many professions, but then the only case in which one would need to ask "What is the name of this fallacy?" would be if you thought an expert had made a logical fallacy and you (a non-expert) had spotted it and wish to communicate the matter. Experts talking to each other about known fallacies will already know the names of them by virtue of being experts. One might seek to learn the names, for that purpose, but the name would be useless to that endeavour without understanding the fallacy it named, at which stage one could dismiss a faulty argument logically without resorting to the name.
Neither is giving it a name going to act as shorthand as you will undoubtedly have to go on to explain what the fallacy is, doubling the time spent expounding the matter. If simply naming the thing were truly enough to satisfy the opponent that their argument is flawed, then your opponent would have to know of the fallacy too, but have used it anyway, a possible but unlikely scenario.
Nor do I accept the argument that names (in this case) help us organise our knowledge or dissect the logical flaws. Were this the intention, then some form of categorisation would have been developed something which truly organised in such a way as to aid the understanding of how such an argument is a fallacy. I cannot see any way in which the current naming system provides such an insight. Despite the efforts of the page's authors, the Wikipedia page you link to is little more than just a list, any categorisation is done post hoc.
I don't think it would realistic to expect that a commonly occurring fallacy would exist for long without someone giving it a name, and I don't doubt that desire would be partly motivated by ease of communication, but our history, especially in philosophy, is not one of free and generous distribution of knowledge but retention and obfuscation in an attempt to retain the power that knowledge gives. Naming is part of that history, naming a fallacy rather than simply explaining it, puts the user in a position of power, one in which they appear to have access to some information their opponent does not. I think the whole "name this fallacy..." game is very appealing because it is such an easy route to the appearance of knowledge, in the same way as direct quotes always seem more attractive in an argument than paraphrasing even though the latter shows more understanding, the former shows more knowledge, and knowledge is equated with power.